In offset printing groups, the surface pressure required for ink transfer is achieved by compressing an elastic medium, such as, for example, a rubber coating, a printing cloth, a sleeve, or the like. To this end, a defined distance of the printing cylinder surfaces is set in the course of assembly and defines a print position. For various reasons it is necessary to set the cylinders in a contact-free manner.
In web-fed rotary printing presses, the printing cylinders are maintained in the print-on position in a geometrically defined position by stops. Three-ring bearings with eccentric rings are used for changing the positions of the centers of the cylinders. A movement of the center of a cylinder in the plane takes place by turning the eccentric rings. This way of realizing the eccentric displacement of the cylinder, by the use of levers and pneumatic actuation, entails various disadvantages. For one, a limitation of the structural space is caused because of synchronous spindles, typically located on each side I/side II, for each cylinder. Secondly, a large adjustment outlay is required because of an over-defined system, such as stops on S1 and S2, coupled by the synchronous spindle, and coupling of the horizontal and vertical displacement device. Thirdly, a great outlay for assembly is typically required.
Individual linear bearings for two transfer cylinders, each seated in a carriage, are known from WO 02/081218 A2. An actuating gear for the carriage can be embodied as a cylinder, which can be charged with a pressure medium. An adjustable stop is provided in order to define an end position for the actuating movement, which end position occurs transversely with respect to the cylinder plane. Actuation is performed by the use of a lever mechanism that is acting on the bearing block, which lever mechanism is actuated, for example, by a hydraulic cylinder and is synchronized on both sides by a synchronizing spindle.
U.S. Pat. No. 6,494,138 B1 discloses a device for seating cylinders, having a bearing block which is movable along an actuating path in linear bearings. The actuating direction S essentially coincides with a connecting plane of the axes of rotation of the cylinders which are to be placed against each other. The linear bearing has bearing elements which are fixed on the frame and are movable.
USP 2001/035 104 A1 also shows a device for seating cylinders, having a bearing block which can be moved along an actuating path in linear bearings. Fixation stations have been assigned to the forme cylinder, which stations are seated, linearly movable, on guide elements which are screwed to lateral frames.
DE 101 45 322 A1 discloses a seating unit of a cylinder, having a bearing block which is linearly movable in respect to a connecting structure in linear bearings and has a rotary bearing. The bearing block can be moved by the use of a displacement device.